City K and City L are 350 km apart. At 2.55 p.m., Sam is travelling at a uniform speed left City K for City L while Tim set off from City L to City K along the same road at a uniform speed, which was 7 km/h slower than that of Sam. The two met at 4.55 p.m.

1. Find the speed of Sam.
2. If Tim continued to travel at the same speed, how long would it take for him to reach his destination after the two met? Express your answer in mixed number.

(a)
Time taken for Sam and Tim to travel from 2.55 p.m. to 4.55 p.m. = 2 h

Average speed of Sam and Tim
= 350 ÷ 2
= 175 km/h

Sam's speed
= (175 + 7) ÷ 2
= 182 ÷ 2 
= 91 km/h

(b)
Tim's speed
= 91 - 7
= 84 km/h

Distance that Tim travelled in 2 h
= 2 x 84
= 168 km

Remaining distance that Tim needed to travel
= 350 - 168
= 182 km

Time that Tim needed to reach his destination after the two met
= 182 ÷ 84
= 2¹⁴₈₄
= 2¹₆ h

Answer(s): (a) 91 km/h; (b) 2¹₆ h